Water quality is one of the main indicators of the quality of service provided to consumers. Quality has an impact on both the public health and aesthetic value of water as a consumable product. Kenya is classified as...Water quality is one of the main indicators of the quality of service provided to consumers. Quality has an impact on both the public health and aesthetic value of water as a consumable product. Kenya is classified as a water-scarce country with only 647 cubic meters of renewable freshwater per capita. Water distributed in Nairobi is faced with a myriad of challenges leading to a compromise to its quality. This study focused on evaluating quality of drinking water since human health depends on adequate, clean, reliable water. Analyses were carried out at National Environmental Management Authority (NEMA) accredited Jomo Kenyatta University of Agriculture and Technology (JKUAT) laboratories to determine the chemical, bacteriological and physical characteristics of consumed water in Umoja Innercore Estate in Nairobi. In the study area, 7 HH and 6 BH sites were randomly distributed. pH, turbidity and temperature measurements were analyzed in-situ while bacteria and chemicals were analyzed in laboratories. The study found that 100% of boreholes recorded unsatisfactory water with up to 1100 of Escherichia coli (E. coli) showing high contamination with faecal coliforms and 83% of boreholes recording pH of up to 9.53. Dissolved oxygen was 5.08 mg/L below recommended 12.0 mg/L, salinity of 0.47 mg/L and 0.03 mg/L for boreholes and households respectively. The study reveals the deprived quality of water available to the residents of Umoja Innercore, Nairobi. The study recommends the use of biosand filtration methods for septic tanks, digging of deeper boreholes and lining septic tanks with impermeable materials to prevent contamination of ground water with raw water from septic.展开更多
Development of graphene field effect transistors （GFETs） faces a serious challenge of graphene interface to the dielectric material. A single layer of intrinsic graphene has an average sheet resistance of the order ...Development of graphene field effect transistors （GFETs） faces a serious challenge of graphene interface to the dielectric material. A single layer of intrinsic graphene has an average sheet resistance of the order of 1-5 kΩ/□. The intrinsic nature of graphene leads to higher contact resistance yielding into the outstanding properties of the material. We design a graphene matrix with minimized sheet resistance of 0.185 kΩ/□ with Ag contacts. The developed matrices on silicon substrates provide a variety of transistor design options for subsequent fabrication. The graphene layer is developed over 400 nm nickel in such a way as to analyze hypersensitive electrical properties of the interface for exfoliation. This work identifies potential of the design in the applicability of few-layer GFETs with less process steps with the help of analyzing the effect of metal contact and post-process anneMing on its electrical fabrication.展开更多
Introduction: Sever sepsis and septic shock contributes to maternal morbidity and mortality. The etiology of sever sepsis and septic shock during pregnancy and postpartum result from obstetric related or non-obstetric...Introduction: Sever sepsis and septic shock contributes to maternal morbidity and mortality. The etiology of sever sepsis and septic shock during pregnancy and postpartum result from obstetric related or non-obstetric related conditions. Objectives: It aimed to determine rate, characters, morbidity and mortality of septic obstetric cases at Omdurman New Hospital. Methods: It was a descriptive, prospective, analytic, cross-sectional hospital based total coverage study;conducted at Omdurman New Hospital (ONH), Khartoum-Sudan. Results: Sever sepsis and septic shock rate 1.16 (13/1124 = 1.16%) of hospital pregnancy complication admission. Hyperthermia, Tachycardia and hypotension are the main presenting clinical findings and uterine infection is the main focus of sepsis. The mean average Intensive Care Unit (ICU) stay is 6.3-day. Organs dysfunctions are the main morbidity and mortality is reported in five cases. Conclusion: Sever sepsis and septic shock contributes in maternal morbidity and mortality. Safe obstetric care prevents maternal sepsis and improves the outcome. Management of sever sepsis and septic shock remains a challenge in obstetric medicine.展开更多
In this article, we have effectively used the Numerical Inversion of Laplace transform to study the time-dependent thin film flow of a second grade fluid flowing down an inclined plane through a porous medium. The sol...In this article, we have effectively used the Numerical Inversion of Laplace transform to study the time-dependent thin film flow of a second grade fluid flowing down an inclined plane through a porous medium. The solution to the governing equation is obtained by using the standard Laplace transform. However, to transform the obtained solutions from Laplace space back to the original space, we have used the Numerical Inversion of Laplace transform. Graphical results have been presented to show the effects of different parameters involved and to show how the fluid flow evolves with time.展开更多
This study presents theoretical considerations and results of a portable shell and tube heat exchanger in a solar water distiller system. The device is composed of a glass heat exchanger, which served as a condenser f...This study presents theoretical considerations and results of a portable shell and tube heat exchanger in a solar water distiller system. The device is composed of a glass heat exchanger, which served as a condenser for vapor condensing which were produced in black paint solar absorber. It was also composed of a tank for water source and a tank for produced distilled water. Shell and tube was designed and simulated using an implicit numerical scheme. Simulation results showed that accumulated mass water greatly depended on the inlet vapor temperature and volume, heat exchanger material, coolant water temperature and volume. Thus, changing the material from stainless steel to glass in the same condition （vapor temperature, vapor volume, coolant temperature and coolant volume）. These inexpensive shell and tube heat exchangers permitted to produce 40 litre/day, distilled water from vapor with 378 K inlet temperature in atmosphere pressure. If inlet pressure increases, vapor temperature will decline and thereupon, heat exchanger＇s efficiency tangibility will increase.展开更多
文摘Water quality is one of the main indicators of the quality of service provided to consumers. Quality has an impact on both the public health and aesthetic value of water as a consumable product. Kenya is classified as a water-scarce country with only 647 cubic meters of renewable freshwater per capita. Water distributed in Nairobi is faced with a myriad of challenges leading to a compromise to its quality. This study focused on evaluating quality of drinking water since human health depends on adequate, clean, reliable water. Analyses were carried out at National Environmental Management Authority (NEMA) accredited Jomo Kenyatta University of Agriculture and Technology (JKUAT) laboratories to determine the chemical, bacteriological and physical characteristics of consumed water in Umoja Innercore Estate in Nairobi. In the study area, 7 HH and 6 BH sites were randomly distributed. pH, turbidity and temperature measurements were analyzed in-situ while bacteria and chemicals were analyzed in laboratories. The study found that 100% of boreholes recorded unsatisfactory water with up to 1100 of Escherichia coli (E. coli) showing high contamination with faecal coliforms and 83% of boreholes recording pH of up to 9.53. Dissolved oxygen was 5.08 mg/L below recommended 12.0 mg/L, salinity of 0.47 mg/L and 0.03 mg/L for boreholes and households respectively. The study reveals the deprived quality of water available to the residents of Umoja Innercore, Nairobi. The study recommends the use of biosand filtration methods for septic tanks, digging of deeper boreholes and lining septic tanks with impermeable materials to prevent contamination of ground water with raw water from septic.
文摘Development of graphene field effect transistors （GFETs） faces a serious challenge of graphene interface to the dielectric material. A single layer of intrinsic graphene has an average sheet resistance of the order of 1-5 kΩ/□. The intrinsic nature of graphene leads to higher contact resistance yielding into the outstanding properties of the material. We design a graphene matrix with minimized sheet resistance of 0.185 kΩ/□ with Ag contacts. The developed matrices on silicon substrates provide a variety of transistor design options for subsequent fabrication. The graphene layer is developed over 400 nm nickel in such a way as to analyze hypersensitive electrical properties of the interface for exfoliation. This work identifies potential of the design in the applicability of few-layer GFETs with less process steps with the help of analyzing the effect of metal contact and post-process anneMing on its electrical fabrication.
文摘Introduction: Sever sepsis and septic shock contributes to maternal morbidity and mortality. The etiology of sever sepsis and septic shock during pregnancy and postpartum result from obstetric related or non-obstetric related conditions. Objectives: It aimed to determine rate, characters, morbidity and mortality of septic obstetric cases at Omdurman New Hospital. Methods: It was a descriptive, prospective, analytic, cross-sectional hospital based total coverage study;conducted at Omdurman New Hospital (ONH), Khartoum-Sudan. Results: Sever sepsis and septic shock rate 1.16 (13/1124 = 1.16%) of hospital pregnancy complication admission. Hyperthermia, Tachycardia and hypotension are the main presenting clinical findings and uterine infection is the main focus of sepsis. The mean average Intensive Care Unit (ICU) stay is 6.3-day. Organs dysfunctions are the main morbidity and mortality is reported in five cases. Conclusion: Sever sepsis and septic shock contributes in maternal morbidity and mortality. Safe obstetric care prevents maternal sepsis and improves the outcome. Management of sever sepsis and septic shock remains a challenge in obstetric medicine.
文摘In this article, we have effectively used the Numerical Inversion of Laplace transform to study the time-dependent thin film flow of a second grade fluid flowing down an inclined plane through a porous medium. The solution to the governing equation is obtained by using the standard Laplace transform. However, to transform the obtained solutions from Laplace space back to the original space, we have used the Numerical Inversion of Laplace transform. Graphical results have been presented to show the effects of different parameters involved and to show how the fluid flow evolves with time.
文摘This study presents theoretical considerations and results of a portable shell and tube heat exchanger in a solar water distiller system. The device is composed of a glass heat exchanger, which served as a condenser for vapor condensing which were produced in black paint solar absorber. It was also composed of a tank for water source and a tank for produced distilled water. Shell and tube was designed and simulated using an implicit numerical scheme. Simulation results showed that accumulated mass water greatly depended on the inlet vapor temperature and volume, heat exchanger material, coolant water temperature and volume. Thus, changing the material from stainless steel to glass in the same condition （vapor temperature, vapor volume, coolant temperature and coolant volume）. These inexpensive shell and tube heat exchangers permitted to produce 40 litre/day, distilled water from vapor with 378 K inlet temperature in atmosphere pressure. If inlet pressure increases, vapor temperature will decline and thereupon, heat exchanger＇s efficiency tangibility will increase.
